This invention is related to the method of making heat-resistant polyester with reduced amount of the end carboxyl group (hereinafter this will be written as COOH).
Various methods of reducing the COOH of polyester have been proposed. Among them the method of reacting the polyester with epoxy compound is known as the typical example. However, the present inventors have examined this method and found out that the known epoxy compound has poor reactivity with the COOH of polyester, giving insufficient effect.